Browse 11 weight loss and metabolic peptides tracked on Peptigrity, with verified third-party HPLC purity data, shop coverage, and mechanism research for each. The compounds below span four mechanism classes: GLP-1 receptor agonists, dual and triple incretin agonists, amylin analogs, and metabolic modulators. Use the "How to choose" section to identify which class fits your research goal, then click into individual compound profiles for trial data, purity reports, and shop comparisons.
Last updated: April 2026
Choose by mechanism class first. The four classes target weight loss through distinct biological pathways with very different evidence bases — picking the right starting point matters more than picking the "strongest" compound.
For head-to-head comparisons of the highest-volume options, see the semaglutide vs tirzepatide comparison and the retatrutide vs tirzepatide vs semaglutide comparison.
GLP-1 (glucagon-like peptide-1), GIP (glucose-dependent insulinotropic polypeptide), and glucagon are gut and pancreatic peptide hormones that regulate post-meal glucose, insulin secretion, and satiety. GLP-1 receptor agonists slow gastric emptying, suppress appetite via central nervous system pathways, and enhance glucose-dependent insulin release. GIP co-agonism amplifies the metabolic and weight-loss effect; glucagon co-agonism adds increased energy expenditure on top.
Amylin is a separate pancreatic peptide that complements insulin signaling and reinforces satiety through different brain pathways than GLP-1 — which is why amylin analogs combine well with GLP-1 agonists in research protocols.
The non-incretin compounds in this category act on entirely different systems. MOTS-C, encoded within mitochondrial DNA, modulates AMPK and metabolic homeostasis. 5-Amino-1MQ inhibits nicotinamide N-methyltransferase (NNMT), an enzyme implicated in adipocyte energy storage. AICAR activates AMPK as an exercise mimetic. HGH Fragment 176-191 isolates the lipolytic C-terminal region of growth hormone without GH's growth-promoting effects. Adipotide is a peptidomimetic that targets prohibitin on the vasculature of white adipose tissue.
For deeper background on peptide therapeutics generally, see how peptides are made.
Weight loss peptides are the most-counterfeited compounds on the research peptide market. Two specific risks apply:
UNDER-DOSING: Semaglutide and tirzepatide are commonly under-filled relative to label claim — the most frequent failure mode in Peptigrity's lab test database. Verify both HPLC purity ≥98% and mass spectrometry quantity match before trusting a vendor's labeled mg/vial.
IDENTITY SUBSTITUTION: Retatrutide, tirzepatide, and semaglutide elute at similar HPLC retention times under common methods. Identity confirmation by mass spectrometry (matching the compound's exact molecular weight) is essential. Peptigrity's lab database flags identity mismatches.
Tirzepatide has the most verified lab tests, followed by retatrutide and semaglutide. Per-compound test counts are visible on each compound's individual page above. The aggregated lab database holds 3,500+ third-party tests across all peptide categories, with weight loss compounds representing the largest share due to vendor and buyer demand.
Tirzepatide has the most verified lab tests, followed by retatrutide and semaglutide. Per-compound test counts are visible on each compound's individual page above. The aggregated lab database holds 3,500+ third-party tests across all peptide categories, with weight loss compounds representing the largest share due to vendor and buyer demand.
Three. Semaglutide (FDA-approved as Wegovy for chronic weight management and Ozempic for type 2 diabetes), tirzepatide (FDA-approved as Zepbound for weight management and Mounjaro for type 2 diabetes), and liraglutide (older GLP-1 agonist, not currently tracked separately on Peptigrity). All other compounds in this category are investigational research compounds without FDA approval.
→ See the FDA peptide regulation timeline:
/blog/fda-peptide-regulation-2025-2026-the-complete-timeline
Three. Semaglutide (FDA-approved as Wegovy for chronic weight management and Ozempic for type 2 diabetes), tirzepatide (FDA-approved as Zepbound for weight management and Mounjaro for type 2 diabetes), and liraglutide (older GLP-1 agonist, not currently tracked separately on Peptigrity). All other compounds in this category are investigational research compounds without FDA approval.
→ See the FDA peptide regulation timeline:
/blog/fda-peptide-regulation-2025-2026-the-complete-timeline
In the United States, FDA-approved versions (Wegovy, Ozempic, Zepbound, Mounjaro) require a prescription. Compounded versions have changed status multiple times in 2024-2026.
→ Can you get semaglutide without a prescription:
/blog/can-you-get-semaglutide-without-a-prescription
→ Do you need a prescription for retatrutide:
/blog/do-you-need-a-prescription-for-retatrutide
→ Country-specific status:
/blog/are-peptides-legal-regulatory-status-by-country
In the United States, FDA-approved versions (Wegovy, Ozempic, Zepbound, Mounjaro) require a prescription. Compounded versions have changed status multiple times in 2024-2026.
→ Can you get semaglutide without a prescription:
/blog/can-you-get-semaglutide-without-a-prescription
→ Do you need a prescription for retatrutide:
/blog/do-you-need-a-prescription-for-retatrutide
→ Country-specific status:
/blog/are-peptides-legal-regulatory-status-by-country
Each compound has different reconstitution and dosing math. Use the general peptide calculator for any compound, or the compound-specific calculators where available — currently BPC-157, GHK-Cu, and MOTS-C have dedicated tools. Unit conversion for semaglutide and tirzepatide (a common source of confusion) is covered in dedicated dosing guides.
→ General peptide calculator: /peptide-calculator
→ MOTS-C calculator: /tools/mots-c-calculator
→ Semaglutide dosing chart: /blog/semaglutide-dosing-chart-units-conversion-side-effects
→ Tirzepatide dosing guide: /blog/tirzepatide-dosing-guide-titration-units-reconstitution
Each compound has different reconstitution and dosing math. Use the general peptide calculator for any compound, or the compound-specific calculators where available — currently BPC-157, GHK-Cu, and MOTS-C have dedicated tools. Unit conversion for semaglutide and tirzepatide (a common source of confusion) is covered in dedicated dosing guides.
→ General peptide calculator: /peptide-calculator
→ MOTS-C calculator: /tools/mots-c-calculator
→ Semaglutide dosing chart: /blog/semaglutide-dosing-chart-units-conversion-side-effects
→ Tirzepatide dosing guide: /blog/tirzepatide-dosing-guide-titration-units-reconstitution
Research-grade peptides sold by research vendors are not FDA-approved for human use and are sold under "for research only" labeling. Prescription versions (Wegovy, Ozempic, Zepbound, Mounjaro) are manufactured under FDA-regulated cGMP standards with extensive post-marketing surveillance. The active molecule is the same; the manufacturing oversight, supply chain validation, and legal status are not.
→ GMP vs non-GMP peptide manufacturing:
/blog/gmp-vs-non-gmp-peptide-manufacturing-quality-gaps
→ Compounding pharmacy vs research peptide:
/blog/compounding-pharmacy-vs-research-peptide
Research-grade peptides sold by research vendors are not FDA-approved for human use and are sold under "for research only" labeling. Prescription versions (Wegovy, Ozempic, Zepbound, Mounjaro) are manufactured under FDA-regulated cGMP standards with extensive post-marketing surveillance. The active molecule is the same; the manufacturing oversight, supply chain validation, and legal status are not.
→ GMP vs non-GMP peptide manufacturing:
/blog/gmp-vs-non-gmp-peptide-manufacturing-quality-gaps
→ Compounding pharmacy vs research peptide:
/blog/compounding-pharmacy-vs-research-peptide